1. Field of the Invention
The present invention relates to data back-up storage systems for computer systems, and more specifically to streamer devices for transferring data between a computer system and a back-up storage device.
2. Art Background
It has become quite common to perform tape back-up for a computer system. In the early days of computing, mainframe vendors developed half-inch reel-to-reel tape drives, which remain popular in centralized computing environments today. Recently, with the proliferation of personal computer systems came quarter-inch tape drives. Quarter-inch cartridge (QIC) tapes with 5 MBytes of data capacity soon became a popular back-up solution for the stand-alone personal computers. Next came the 8-mm tape format, which uses the standard VHS recording method, helical scan. The primary benefit to early users of 8-mm tape was its ability to store over 2 gigabytes of data on a VHS cassette. Like its quarter-inch and half-inch predecessors, the 8-mm tape employs analog recording methods.
Now comes digital audio tape (DAT) which uses digital recording technology developed originally for DAT devices in the music industry. In 1988, the first DAT drive for storing computer data was introduced. DAT shares with 8-mm tape the ability to store gigabytes of data on a small tape cartridge. Although the two technologies are able to store comparable quantities of data, DAT drives are cheaper to manufacture, which is one of the reasons for DAT's surging popularity in providing multi-gigabyte back-up solutions.
Presently, there are two popular methods for performing memory back-up for the hard disk contents of personal computer systems. The first method is to store the hard disk data of a personal computer system on an optical disk. The data on the optical disk is read by a laser beam. The capacity of a 31/2" optical disk is typically 128 MBytes of data and for a 51/4" optical disk is typically 650 MBytes of data.
The second method is to store the hard disk data on a magnetic tape, such as the ones described above. Several types of tape streamers presently exist in industry. Some use 8-mm digital data storage (DDS) cartridges with maximum capacity of about 2.3 gigabytes; others use 4-mm DDS cartridges with maximum capacity of about 1.3 gigabytes; and others use basic QIC with maximum capacity of 1.3 gigabytes, but more commonly a capacity of around 40-250 MBytes.
There are disadvantages associated with the prior methods. First, the tape in a tape drive must be formatted before use, which becomes a time consuming process as more tapes are used for back-up. Also, the standard QIC may be exposed to fingerprints or dust, since the tape in the cartridge is not protected. This can result in distorted data storage. All existing streamers also require an interface card to be installed in order to function with an intended computer such as an IBM-compatible computer, or an Apple Macintosh computer, which dedicates the streamers to either an IBM-compatible or a Macintosh computer, but not both.
Furthermore, as data back-up storage and retrieval are frequently conducted while the users are away from their desk environments, e.g. traveling executives, streamers' portability and universal compatibility become important issues. A user should be able to download the contents of a hard disk to a readily available storage device anywhere in the world. Additionally, a user sometimes needs to communicate with a remote computer system through a modem, which becomes an additional item to carry on the trip. Therefore, it is desirable to have both the streamer and the modem on a unit, which is also capable of operating in a variety of voltage of, for example, 110 volts and 220 volts. Also, it is desirable to have the modem capable of operating either international or US communication standards.